user
Tell me how would you respond to the following request.
How would you explain the concept of a blockchain to someone who has not heard of it before?

assistant
A blockchain is a decentralized digital ledger that records transactional data in a secure, trustless and immutable manner. It is a decentralized system that allows multiple different parties to transact, store data and keep track of the ledgers without relying on a third-party intermediary like a bank. It utilizes a network of nodes (computers) to reach consensus on the validity of past transactions, ensuring that once data is entered into a block, it can no longer be tampered with. As such, it provides a secure, reliable and efficient way to record and store data.